Bulk delivery apparatus



I FIGI.

Sept. 29, 1970 G. F K o Ts ETAL 3,531,022

BULK DELIVERY APPARATUS Filed Jan. 2, 1969 2511881 41186; 1

' INVENTORSi GEORGE F. KNOTTS HERBERT K. BEYER ROBERT c. KOLB A TYS.

US. Cl. 222-145 United States Patent 3,531,022 BULK DELIVERY APPARATUS George F. Knotts, Coopersburg, Herbert K. Beyer,

Royersford, and Robert C. Kolb, Spring City, Pa., assignors to Amerind-MacKissic, Incorporated, Parker Ford, Pa., a corporation of Pennsylvania Filed Jan. 2, 1969, Ser. No. 788,416

Int. Cl. B67d /60 13 Claims ABSTRACT OF THE DISCLOSURE ,Bulk delivery apparatus including a hammer mill grinder, operable selectively to pulverize the solid ingredient prior to its feed into a mixing chamber where it is mixed with a liquid ingredient and subsequently discharged from the apparatus. The discharge is eifected by pressurized air blown through the mixing chamber and controlled automatically to initiate flow of pressure air through the mixing chamber concurrently with the admission of the two ingredients. thereinto, and to continue the flow of pressure air through the mixing chamber for a predetermined period after the arrest of the feed of the ingredients into the mixing chamber.

The present invention relates to bulk delivery apparatus, and more particularly apparatus for mixing solid and liquid bulk material and discharging the mixture under pressure. The invention has particular application in delivery trucks for ammonium nitrate and fuel oil which are mixed for use as an explosive.

The invention is particlularly adapted for use in delivery apparatus as shown in US. Pat. No. 3,424,438 issued to Knotts et al. which operates to deliver a mixture having a predetermined ratio of fuel oil and ammonium nitrate for depositing into a blast-hole.

Although the apparatus of the above-identified patent is entirely satisfactory for the most common blasting operations, it is desirable to use a mixture of a different character for the charge at the bottom of deep holes than for shallower charges. Furthermore, when problems of water conditions are present in the blasting site, it has been found desirable or necessary to use pre-packaged blasting material which at present must be transported to the blasting site along with the bulk blasting materials.

The present invention provides a delivery apparatus which enables the character of the solid material to be modified prior to its mixture with the liquid so as to accommodate the material discharged from the apparatus to the particular conditions required.

More particularly the present invention provides a grinding device operable at the selection of the operator to pulverize the solid ingredient, normally ammonium nitrate prills, prior to mixing the same with the liquid, normally fuel oil. In the illustrated embodiment of the invention, the solid material from the storage hopper of the apparatus is fed to the mixing chamber of the apparatus through a hammer mill, which when activated operates to pulverize the solid ingredient flowing therethrough, and which when deactivated permits passage of the solid ingredient therethrough 'without pulverization.

Especially when handling pulverized solid material, it has been found desirable to provide means for clearing the mixing chamber of the solid material prior to shutting down the delivery apparatus and at the same time insure termination of the flow of pressure air through the mixing chamber after a predetermined time interval so as to eliminate the possibility of discharge of the explosive mixture from the apparatus during periods of shutdown.

To this end the present invention provides automatic control of the pressure air to automatically initiate flow through the mixing chamber concurrently with the introduction of solid material therethrough and to continue the flow of the pressure air through the mixing chamber for a predetermined short interval following arrest of the feed of the solid and liquid ingredients into the mixing chamber.

More specifically the present invention provides a hydraulic control for the pressure air supply which is coupled to the control of the feed of the ingredients into the mixing chamber, said hydraulic control of the air supply including a time-delay arrangement operable upon shutdown of the ingredient-feed means to defer arrest of the flow of pressure air through the mixing chamber.

All of the objects of the invention are more fully set forth hereinafter with reference to the accompanying drawing wherein:

FIG. 1 illustrates in rear elevation bulk delivery apparatus embodying the present invention;

FIG. 2 is a fragmentary view in side elevation at a reduced scale illustrating the apparatus shown in FIG. 1;

FIG. 3 is an enlarged fragmentary view partially in section showing control means for the pressure air supply embodying the present invention;

FIG. 4 is a sectional view taken on the irregular section line 44 of FIG. 3; and

FIG. 5 is a view illustrating the operating mechanism for the valve of FIGS. 3 and 4, and illustrating schematically the hydraulic drive system for feeding the solid ingredient, and the control means for supplying the liquid ingredient to the mixing chamber.

Referring now to the drawings, and more particularly to FIGS. 1 and 2 thereof, the delivery apparatus comprises a truck having a frame 14 mounted on wheels 15. A hopper body 16 comprising a storage tank for solid material, such as ammonium nitrate prills, is mounted on the frame 14 With bottom Walls 21 of the hopper converging downwardly toward a conveyor system 17 for discharging the material from the hopper 16. In the present instance the conveyor system 17 includes a horizontal feed screw or anger extending longitudinally of the hopper 1-6 coextensive in length therewith and terminating at the rear in an upstanding feed chute 18 having a feed screw 19 rotatably mounted therein to feed the solid material upwardly to a conveyor outlet 20. The horizontal and upright feed screws of the conveyor system 17 are of standard construction, for example, as described more fully in the aforementioned US. patent. The screws are coupled together for simultaneous rotary movement and are driven from a suitable hydraulic drive motor '23 by positve driving connections as indicated at 24.

In accordance with the invention the conveyor system 17 delivers the solid material through a grinding device 26, and an air isolation means 27 to a mixing chamber 28. In the present instance, the device 26 is a hammer mill of conventional design and is connected at 29 to a separate hydraulic motor 31 so it may be either activated or deactivated at the option of the operator, for example by a valve 32. When activated, the hammer mill 26 operates to pulverize the solid material flowing therethrough from the outlet 20 to the isolation means 27, and when deactivated the hammer mill serves to transfer the material therethrough without pulverization.

The selection by the operator between pulverization and lack of pulverization is useful when it is desired to use pulverized prills in the charge at the bottom of a hole but it is preferred to use non-pulverized prills in shallower charges. Thus, when depositing the bottom charges in the hole, the operator will activate the hammer mill grinder, and for shallow charges, the operator will inactivate the grinder by closing the valve 32.

The isolation means 27 is preferably an air lock of the type shown in the aforementioned patent including a vaned rotor which is driven in synchronism with the conveyor system 17, in the present instance through driving connections 33 to the conveyor system 17. The air lock 27 when driven, transfers the solid material from the hammer mill 26 to the mixing chamber 28 while preventing reverse air flow from the mixing chamber 28 upwardly into the hammer mill 26.

Concurrent with the feed of solid material into the mixing chamber 28, a liquid ingredient, for example fuel oil is fed from storage tanks 41 into the mixing chamber from a positive displacement pump 42. As shown in FIGS. 1 and 5, and as described more fully in the aforementioned patent, the oil from the tanks 41 is fed in metered quantities by the positive displacement pump 42 through a pair of guard valves 43 and 44 having a flow meter 45 and pressure gauge 46 positioned therebetween. The oil is introduced into the mixing chamber 28 by injection spray nozzles 48 positioned adjacent the discharge port 47 of the screw at the forward end of the frame 14 (see FIG. 1).

In this manner the synchronized drive of the solid-material feed means and the liquid material feed means permits accurate proportioning of the two ingredients in the mixing chamber.

As in the apparatus disclosed in the aforementioned patent, the mixture is continuously discharged from a mixing chamber 28 concurrently with the feed of material thereto. To this end a pneumatic discharge system is provided including an air inlet conduit 52 connected to an inlet port 53 of the mixing chamber and a pneumatic discharge pipe 54 connected to the outlet port 47. The discharge pipe 54 may have a suitable fitting for receiving either a standard closure or a high pressure hose normally carried in casings 55 along the sides of the hopper 16. Air is supplied to the inlet conduit 52 from a supply conduit 58 connected to a blower (not shown) driven from the power takeoff of the truck chassis, for example as described in the aforementioned patent. The blower is normally operated continuously upon energization of the power takeoff and means is provided to divert the air supply from the inlet conduit 52 when the ingredient feed means are shut down or idle, as for example when changing the pressure hose from one blow hole to another or when inspecting the condition of the charge in the hole. To this end, a diverter valve 61 is mounted intermediate the conduits 58 and 52. The valve 61 comprises a cylindrical casing having an inlet 62 connected to the conduit 58, the first outlet 63 connected to the conduit 52 and a second outlet 64 open to the atmosphere. A flap valve element 65 is rotatably mounted for coaxial rotation in the casing to alternatively connect the inlet 62 with either one or the other of the outlets 63 and 64. As shown in the full line position in FIGS. 3 and 5, the flap valve 65 normally interconnects the inlet 62 with the outlet 64, but by rotating the valve approximately 60 degrees clockwise, the inlet 62 is connected to the outlet 63. Displacement of the valve is effected by an operator 66 (FIG. 5) and hydraulic ram 68 connected for automatic operation in timed relation to the hydraulic motor 23 which operates the conveyor system 17, the air lock 27 and the oil pump 42.

Although it is possible to drive the hydraulic motors 23 and 31 and the hydraulic ram 68 from the hydraulic system of the truck, it is preferred to provide separate hydraulic pumps 71 and 91 driven from the power takeofis of the truck to insure concurrent operation of the hydraulic drive to the conveyor system and the blower.

As shown schematically in FIG. 5, the pump 71 has an inlet 72 connected to a sump 73, and a discharge line 74 connected to a control valve 75 for switching on and off the hydraulic drive system of the apparatus. A safety valve 76 is provided to connect the outlet line 74 to the sump 73 through a bypass 77 when the control valve 75 is closed. When it is desired to introduce the ingredients into the mixing chamber 28, the switching valve 75 is opened to admit hydraulic fluid to the motor 23 and initiate operation of the conveyor system 17, the air lock 27 and the pump 42. Simultaneously with the energization of the motor 23, pressure fluid is introduced to the hydraulic ram 68 through a check valve 81 and an inlet line 82..The hydraulic ram includes a piston 83 which is biased to its retracted position by a spring 84 so as to normally posi tion the valve 61 to divert the discharge pressure from the supply conduit 58 to the outlet 64. When pressure fluid is introduced behind the piston 83, the spring 84 is compressed and the valve is shifted to divert the discharge pressure into the inlet conduit 52 of the mixing chamber 28. Thus in operation, the discharge pressure is supplied to the mixing chamber simultaneously with the introduction of the materials thereinto, and the mixture is discharged through the discharge conduit 54.

When it is desired to arrest the discharge of the material through the conduit 54, the switching valve 75 is released to shut off the supply of hydraulic fluid to the motor 23, simultaneously isolating the hydraulic ram 68 from the hydraulic pressure. In accordance with the invention, to enable continued flow of discharge pressure air through the mixing chamber for a predetermined time, retraction of the hydraulic ram piston 83 is delayed. To this end, the check valve 81 is bypassed by an orifice 86 having a restricted opening correlated to the pressure of the spring 84 to retard the retraction of the piston 83 and therefore delay the return of the valve operator 66 from the broken line position to its full line position. The restriction of the orifice 86 is selected in relation to the force of the spring 84 so as to provide the desired delay in the return of the valve 61, permitting continued supply of discharge pressure air to the inlet line 52 of the mixing chamber 28 for a predetermined period. This predetermined delay permits the discharge pressure to evacuate the mixture remaining in the mixing chamber 28 through the discharge conduit 54. At the conclusion of the timed interval, the supply conduit 58 is connected to the atmosphere through the port 64 and flow of the mixture from the mixing chamber 28 is arrested, permitting disconnection of the pressure hose therefrom and avoiding loss of the mixture during the period when the apparatus is shut down.

The hydraulic motor 31 for the hammer mill 26 is supplied from a pump 91 which is driven from a separate power takeofi. The inlet line 92 of this pump leads from a separate sump 93, and its discharge line 94 connects to the control valve 32 through a safety valve 96 which diverts the fluid through a bypass 97 to the sump when the valve 32 is closed. Thus the hammer mill is operable independently of the conveyor system and blower.

The apparatus of the present invention is thus useful to deposit a charge comprising either pulverized or nonpulverized prills in the blast-hole. However, in blast-holes having a water problem, it is desirable to use packaged charges in the hole instead of a direct deposit of the charge in the hole. The apparatus of the present invention may be used to prepare packaged charges at the site of the blasting operation. Packaged charges normally comprise pulverized prills and the hammer mill grinder is therefore energized when forming packaged charges. The delivery apparatus of the present invention may therefore be used with the grinder in operation to deliver the ingredients to mobile packaging apparatus at the blasting site, or if mobile packaging apparatus is not available, the pressure of the pressurized discharge may be modified to permit employment of manual techniques for the packaging of a charge embodying pulverized prills. Thus the present invention provides wide flexibility in the use of the apparatus and may eliminate the necessity for maintaining a supply of pre-packaged charges at the blasting site,

While a particular embodiment of the present invention has been herein illustrated and described, it is not intended to limit the invention to such disclosure but changes and modifications may be made therein and thereto within the scope of the following claims.

We claim:

1. Bulk delivery apparatus for mixing and dispensing liquid and solid ingredients including a mixing chamber, means to supply a liquid ingredient to said chamber, means to supply a solid ingredient to said chamber, air supply means to supply pressure air to said mixing chamber under pressure and discharge means to discharge the mixture from said chamber under the influence of the air supplied by said air supply means, said solid ingredient supply means including isolation means adjacent the mixing cham ber to prevent the pressure air from flowing back into said solid ingredient supply means from said mixing chamber, a reservoir for solid ingredient, conveyor means operable to feed material from said reservoir through said isolation means to said mixing chamber, a modifying device for said solid ingredient intermediate said conveyor means and isolation chamber and effective upon operation of said conveyor means to conduct the solid materials from said conveyor means into said isolation means, and means to selectively activate and deactivate said modifying device whereby said modifying device, when activated operates to modify the character of the material conducted therethrough, and when inactivated operates to conduct the material therethrough without modifying its character.

2. Apparatus according to claim 1 wherein said modifying device comprises a grinding device operable when activated to pulverize said solid ingredient.

3. Apparatus according to claim 2 wherein said grinding device consists of a hammer mill connected at its upper feed end to said conveyor means and communicating at its lower discharge end with said isolation means.

4. Apparatus according to claim 3 including a first hydraulic motor connected to said liquid-supply means, said conveyor means, and said isolation means to operate the same simultaneously, a separate hydraulic motor connected to said hammer mill to operate said mill, and means to supply hydraulic fluid to said motors, said means to selectively activate and deactivate said hammer mill comprising a valve controlling the flow of hydraulic fluid to said separate hydraulic motor.

5. Apparatus according to claim 4 wherein said air supply means includes a blower operating concurrently with, and for at least a time interval after, the operation of said conveyor means, a diverter valve intermediate said blower and said mixing chamber operable in a first position to divert air from said mixing chamber and prevent flow of pressure air therethrough and in a second position to afiord pressure air flow to and through said mixing chamber, control means for said diverter valve operable to displace said valve to said second position upon initiation of said conveyor means and operable to displace said valve to said first position at a predetermined timed interval following interruption of said conveyor means.

6. Apparatus according to claim 5 wherein said control means includes a hydraulic ram operating said diverter valve to said first position when displaced in one direction, and to said second position when displaced in the opposite direction, means connecting said hydraulic fluid supply means to said ram to displace it in said one direction upon flow of hydraulic fluid thereto, and time delay means to delay opposite displacement of said ram upon interruption of said flow.

7. Apparatus according to claim 6 wherein said hydraulic ram includes a piston biased in said one direction, said connecting means introducing hydraulic fluid into said ram behind said piston to displace the same in said opposite direction against its bias, said time delay means including a check valve affording unidirectional free flow of hydraulic fluid into said ram behind said piston, and an orifice bypassing said check valve afiording reverse flow of hydraulic fluid from said ram under the action of said biased piston at a limited rate upon interruption of hydraulic fluid flow thereto.

8. Bulk delivery and apparatus for mixing and discharging liquid and solid ingredients including a mixing chamber, means to supply a liquid ingredient to said chamber, means to supply a solid ingredient to said chamber, air supply means to supply pressure air to and through said mixing chamber, discharge means to discharge the mixture of said ingredients from said chamber under the influence of the air supplied by said air supply means, common drive means for said liquidand solid-ingredient supply means, independent drive means for said air supply means to supply air concurrently with, and for at least a time interval after, the operation of said common drive means, said air supply means including a diverter valve in advance of said mixing chamber operable in a first position to divert air from said mixing chamber and prevent flow of pressure air therethrough and in a second position to afford pressure air flow to and through said mixing chamber, and control means for said diverter valve coupled to said common drive means to displace said valve to said second position upon initiation of said common drive means and to displace said valve to said first position at a predetermined time interval following interrup tion of said common drive means' 9. Apparatus according to claim 8 wherein said diverter valve is biased toward said first position, and said control means effects free displacement of said valve against said bias to said second position upon initiation of said common drive means and delayed displacement of said valve by said bias to said first position upon interruption of said common drive means.

10. Apparatus according to claim 9 wherein said common drive means comprises a hydraulic motor, a supply of hydraulic pressure fluid, and switching means to selectively initiate and interrupt flow of fluid from said supply through said motor, and

said control means includes a hydraulic ram connected to said valve and having a spring to provide said bias to said valve, and means connecting said ram to said supply means through said switching means.

11. Apparatus according to claim 10 wherein said connecting means includes a check valve afl'ording free flow toward said ram to efiect said free displacement and an orifice bypassing said check valve aifording restricted flow away from said ram to effect said delayed displacement.

12. Apparatus according to claim 10 wherein said hydraulic pressure fluid supply comprises a hydraulic pump connected to said switching means, and said air supply means comprises a blower, said pump and blower being driven concurrently.

13. Apparatus according to claim 8 wherein said diverter valve comprises a casing having an inlet connected to said air supply, a first outlet connected to said mixing chamber, a second outlet open to the atmosphere, and a valve element operable to alternatively connect said inlet with one of said outlets.

References Cited UNITED STATES PATENTS 2,299,565 10/1942 Colburn 222194 X 3,424,438 1/1969 Knotts et al. 2594 STANLEY H. TOLLBERG, Primary Examiner US. Cl. X.R. 222l; 2594 

